WLAN Bluetooth Coexistence via Filter and Power Control

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Solution Overview

Problem

Existing techniques for co-existence of WLAN and Bluetooth signals, such as time sharing and adaptive frequency hopping, are inadequate in emerging platforms with low antenna isolation and increased Bluetooth transmit power, leading to significant degradation of WLAN throughput due to interference.

Innovation Solution

Adjusting the filter response characteristics of programmable baseband digital filters to increase attenuation of Bluetooth signals, identifying a larger operating bandwidth for Bluetooth to avoid, and adaptively reducing Bluetooth transmit power based on antenna isolation and WLAN receive status.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If Bluetooth transmit power is increased, then Bluetooth signal strength is improved, but WLAN throughput is degraded due to interference

Engineering Contradiction:

ImproveBluetooth transmit powerVSAvoidWLAN throughput

Core Design Contradiction:

PowerVSProductivity

Solution Approach 1:

The patent dynamically adjusts Bluetooth transmit power based on WLAN activity detection. When WLAN traffic is detected, the Bluetooth transmit power is reduced or transmissions are suspended, preventing interference with WLAN throughput while maintaining adequate Bluetooth signal strength during normal operation

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The system implements a feedback mechanism where the WLAN radio monitors for incoming traffic and communicates this status to the Bluetooth radio. This feedback loop enables real-time coordination, allowing the Bluetooth radio to adapt its transmit power or transmission timing based on WLAN activity, thus resolving the interference issue

Inventive Principle:

Principle #23Feedback

2Object-affected harmful factors

If time sharing technique is used, then interference between WLAN and Bluetooth is reduced, but WLAN throughput is degraded due to transmission delays

Engineering Contradiction:

ImproveinterferenceVSAvoidWLAN throughput

Core Design Contradiction:

Object-affected harmful factorsVSProductivity

Solution Approach 1:

Instead of strict time sharing, the patent employs periodic WLAN traffic monitoring while allowing Bluetooth to transmit continuously at adjusted power levels. This periodic detection approach maintains WLAN throughput by avoiding transmission suspensions while still identifying when to reduce Bluetooth power to minimize interference

Inventive Principle:

Principle #19Periodic action

3Object-affected harmful factors

If adaptive frequency hopping is used, then interference between WLAN and Bluetooth is reduced, but device complexity is increased

Engineering Contradiction:

ImproveinterferenceVSAvoiddevice complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent simplifies the coexistence mechanism by changing only the power parameter rather than implementing frequency hopping. This approach reduces device complexity while still effectively managing interference through dynamic power adjustment based on WLAN traffic conditions

Inventive Principle:

Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Significantly reduces interference between WLAN and Bluetooth signals, maintaining WLAN throughput by enhancing signal attenuation and power control, thereby improving co-existence in platforms with low antenna isolation.

Implementation Method 1

Adjusting the filter response characteristics of programmable baseband digital filters to increase attenuation of Bluetooth signals

Methodology Applied

Scientific EffectSignal attenuation: Absorption (EM radiation)

Data Source

PatentUS8457559B2Techniques to improve the radio co-existence of wireless signals

Publication Date: 2013.06.04 INTEL CORP

AI summary

Techniques are described that can be used to perform one or more of the following actions in order to reduce signal interference between WLAN and BlueTooth radios that are proximate to one another. One action is to selectively reduce a filter bandwidth in a WLAN radio applied to a received WLAN radio signal to reduce BlueTooth signal interference. An additional or alternative action is to selectively indicate a WLAN radio channel bandwidth larger than a channel bandwidth used for the WLAN radio so that the BlueTooth radio avoids transmitting over the indicated channel bandwidth. An additional or alternative action is to selectively reduce BlueTooth transmitter power in response to antenna isolation between BT and WLAN radio being less than a first threshold in order to reduce the likelihood of WLAN radio front end saturation.